Actually I managed to figure this out with the help of a KNIME team member.
I am documenting the solution below for anyone else experiencing the problem - note, this was a GMAIL specific setup:
- Send Email node worked in AP but not in Server, using Gmail email credentials
- There are several things to make the Send Email node work for Gmail in Server:
- Allow “less secure” apps - https://support.google.com/accounts/answer/6010255?hl=en
- Log into your Google account - account.google.com
- Go to Security
- Go to Signing in to Google
Here you must set 2 things:
a. Set-up 2-step verification. This will either make you verify through a mobile or other method
b. Set-up an App Password. This will generate a new password for you - specific to use with an external app. It should look like this:
- Next, go to the KNIME workflow, use the Credentials configuration node to feed the Send Email node - but use the Google App Password instead of the regular email password!
This setup should work with both AP and Server!
If there is any issue with running on Server then double check Server Execution Options - potentially the App password will need to be entered here too:
Hope this helps someone else facing this challenge.
Now, to figure out the Microsoft Exchange and Yahoo sending methods 